This invention relates to a developer sealing device for a zerographic copying machine which device serves to provide a seal between a rotating photosensitive member and the end of the housing of a cleaning or developing unit.
A xerographic copying machine must be provided with means for sealing the gap between the cleaning unit or developing unit and the rotating photosensitive member for the purpose of preventing developer from being leaked out of the cleaning or developing unit. In the past, two arrangements have been used to provide the required seal. In one, the ends a of the cleaning unit or developing unit housing are positioned as near to the photosensitive member b as possible as shown in FIG. 1. In the other, films c are attached to the ends a of the housing and are in contact with the photosensitive member b as shown in FIG. 2.
In the first case, it has been found that when the ends a of the housing are sufficiently close to the photosensitive member b that a developer will not be leaked out from the developing unit, the ends a scratched the member b due to the eccentric displacement or the like of the member b. In the case of the second arrangement, the films c not only tear the photosensitive member b in long-term usage, but the films c when attached to the entrance of the cleaning unit scrape off the residual developer which should instead be scraped off in the cleaning unit or when attached to the exit of the developing unit sweep off the developed picture.